The present invention relates to a baling machine for forming cylindrical bales of crop.
Machines, towed by a tractor, for forming large cylindrical bales of hay (so called "round balers") are well-known. As the machine advances, the crop is removed from a windrow by a pick-up mechanism and delivered rearwardly to a baling chamber where it is rolled into a bale.
There are basically two forms of such machines, namely those with a fixed volume baling chamber defined by driven fixed-position rolls and those with a baling chamber defined by runs of belts (driven by belt rolls over which they are entrained) which move outwardly to enlarge the chamber to accommodate the bale as it grows in size. In both forms the hay is caused by the driven movement of the rolls or belts to roll round upon itself into a core and the core rotates about its horizontal axis and finally an completed bale is formed, the chamber being fed throughout with hay. The completed bale is tied with twine to maintain its shape and is discharged through a gate formed by a rear portion of the machine. A machine with fixed-position rolls, i.e., with a constant volume baling chamber, will produce a bale with a "soft" core and dense outer layers while one with movable-position belts, i.e., with a variable volume baling chamber, will make a uniformly dense bale. The latter machine can be more compact in a lengthwise direction in that the baling chamber can in one design be fed from the underside rather than via a pick-up mounted on the front as is the case with the former machine.
Round balers having both rolls and belts have been proposed. One such machine, described GB-A-2 128 542, published May 2, 1984, has an upper forward part of the baling chamber defined by fixed-position driven rolls and the remaining lower and rearward part by a plurality of fixed-position belt conveyors. The baling chamber is thus of constant volume.
A machine of variable volume has been disclosed in GB-A-2 090 560, published July 14, 1982. Here the lower part of the baling chamber is defined by fixed-position rolls and the upper part by variable-position belt conveyors. The two machines have in common that they are fed via a pick-up located at the front.
Those machines of which the baling chamber is of constant volume clearly cannot be used to produce bales of different sizes as can the variable chamber balers. On the other hand, it is not simple in a variable volume chamber to wrap the bale with net or sheet material, rather than twine, as is now often favored.